Computational Physics Video 31 - Writing a Monte Carlo Radiation Transport Code

[@KevinWeatherwalks]

At 19:00 shouldn't it be ravg = mean(r); ? mean(r(j)) would be taking the average of just a single value, no?

[@syahrildeutch]

I think so, it should be mean(r). Anyway it's great tutorial. Thank you Mr Owen

[@elhussienhassansirelkhatim4436]

So nice. Thank you for this great and clear explanation. I hope if it is possible to add extra two cods for photon and electron in therapeutic range of energy

[@jakemuff9407]

Great vid but would help having the source code to play around with! Also, in this example is there an theoretical way to estimate it through symmetry?

[@paragrane4760]

You are great

[@khararboy]

Dear sir I m also working on monte carlo technique but with photons... Your lecture is very best as it is moving in same direction as I was thinking. Sir I have doubt regarding absorption of photon. Suppose if photon are from 0.1 to 2 micrometer wavelength range. Let say one photon at particular wavelength absorbed. How would I know the total energy of photons absorbed in same code as you put for neutron. Kindly suggest

[@HywelOwen]

Your question is not specific. Please re-word it.

[@khararboy]

Dear sir if we take photon of sun light from wavelength 0.1 to 2.5 micrometer. How we would analyse the photon energy in similar program. SAY if photon absorbed than how to express their energy after absorption. If N =1000 and they absorb randomly on different wavelength. What would be total absorbed photon energy and their count.... As you did for tin and tout

[@HywelOwen]

@@khararboy Your question is still not clearly worded.

[@khararboy]

Can you give one lecture on solar photon transport on solar collector based on monte carlo technique

[@HywelOwen]

@@khararboy Not really, no.

[@dr_ashraf-hamedgad5700]

Can you help me, I want the attenuation factor of neutron transportation......an example when *( thermal neutron flux 10^4) transport in a 10 cm sheet of polyethylene....give me the results and your program sheet

[@HywelOwen]

You can calculate the numbers you want using the method I describe, but you should not use this code for any safety-critical purpose. Also, this is a basic introduction and you should not that attenuation of neutrons in shielding is not a simple process.

[@walidahammed2350]

Hello sir,Thanks for making a such a good tutorial. Why don't you make another tutorial on fluka ? It'd be really helpful for those who want to learn this.

[@HywelOwen]

This is a course on how radiation transport is done, not a course about particular codes. There is lots of teaching material online about FLUKA.

[@waqasahmad0112]

Can you help me with coding the MC simulation program for multiple scattering of photon considering the polarized light?

[@HywelOwen]

Sorry, no! But you can take this module as part of our degree in physics at Manchester.

[@waqasahmad0112]

@@HywelOwen May I know your email please

[@Rugbylover39]

Hi, I've written a monte carlo program that calculates fluence as a function of depth in a multilayer medium for photon transport. The code appears to work well when I store the absorption positions in a cartesian array, but when I attempt to store in cylindrical coordinates, the fluence along the z axis is very low. The source is an infinitely narrow beam at the origin with unity direction along the z axis. I'm sorry, it's probably difficult to troubleshoot without seeing the code, but is there any solution that might come to mind? The number of launched particles is not an issue. Thank you.

[@Rugbylover39]

Edit: I understand that in cylindrical coordinates, the element volume is small along the z-axis due to the small radial displacement. But I don't believe this is the cause as I have already normalized the absorption array by the element volumes.

[@HywelOwen]

@@Rugbylover39 You probably need to multiply your fluence by 1/r.

[@Rugbylover39]

@@HywelOwen Thank you so much! I did have an issue with correctly calculating my volume!

[@HywelOwen]

@@Rugbylover39 Jacobian

[@oussamaelkhiar9721]

hello sir, can i know where do the formulas for s and theta and phi come from please ?

[@HywelOwen]

These are explained in an earlier video in the series.

[@oussamaelkhiar9721]

Thank you very much ! Can i please ask one more thing, why exactly do we need an exponentially distibuted sampling for our step ? Why isnt the neutron step just uniformly distributed ? Physically is it because of energy loss ? Thank you so much for your time and effort

[@HywelOwen]

@@oussamaelkhiar9721 Again, this is covered in earlier videos: 27, 28, 29

[@grzegorzzielonka7217]

Hi, have you tried to simulate such process in Flair Fluka ?

[@HywelOwen]

Yes, you can use codes such as Fluka to do radiation transport. The three main codes I see used are MCNP, GEANT4 and Fluka. The point of my video is so that people can learn how codes like Fluka work; they all work in basically the same way. However, if you are doing real-world predictions of radiation transport then you should use an appropriate code. The benefit of codes like Fluka is primarily that they have been thoroughly debugged and that the cross-section tables have been benchmarked against real situations.

[@petrussegetmena6041]

Can your get your code?

[@HywelOwen]

I don’t understand your question.

[@petrussegetmena6041]

@@HywelOwen sorry Hywel, i mean can i get your code?

[@petrussegetmena6041]

I am very interested in your explanation of this material.

[@HywelOwen]

@@petrussegetmena6041 The code is shown in this tutorial video. The idea is that you write your own program while you're watching this video; that way you learn how the code works. The code is not practically useful though - I mean, you can't use it for real-world applications. For that, you should use a professional tool such as GEANT4.

[@petrussegetmena6041]

@@HywelOwen Thank you for replying to my comment, I really appreciate it

[@marwanabas5524]

you are whispering!! with full volume sounds and I hear nothing!!

[@HywelOwen]

Marwan Abas Your speakers aren’t working.